Organic silicon compound, resist, thermal polymerization composition and photopolymerization composition

ABSTRACT

Disclosed are an organic silicon compound having a repeating unit represented by general formula (I) shown below, a resist, a thermal polymerization composition and a photopolymerization composition containing the organic silicon compound,    &lt;IMAGE&gt;group, R2 is an hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 24 carbon atoms, a substituted or unsubstituted aryl group having 1 to 24 carbon atoms, or a substituted or unsubstituted aralkyl having 7 to 24 carbon atoms, R3 is a substituted or unsubstituted alkyl group having 1 to 24 carbon atoms, a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 24 carbon atoms or an alkoxyl group, and k represents an integer from 0 to 4.

This is a Division of application Ser. No. 08/490,614 filed on Jun. 15,1995, now U.S. Pat. No. 5,624,788.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic silicon compound which canbe easily decomposed by light, heat or acid. The invention is alsorelated to a resist, a thermal polymerization composition and aphotopolymerization composition using the organic silicon compound.

2. Description of the Related Art

Polysilane is an organic silicon compound having an Si--Si structure asa main chain and usually a hydrophobic group such as an alkyl group oran aryl group as a side chain, which is photoreactive since σ electronsof the Si--Si bond are delocalized. For its photoreactivity, thepolysilane is expected to be used as a resist and a photopolymerizationinitiator for a long time.

For example, Jpn. Pat. Appln. KOKOKU Publication No. 3-79377, disclosesa polysilane which may be employed as a positive-working resist.However, the conventional polysilane is not sufficiently photoreactive,it can hardly serve to form high-precision fine patterns when it is usedsingly as photoresist.

Journal of Radiation Curing, January 1986, pp. 35-40, discloses anattempt to use a polysilane as a polymerization catalyst for a compoundhaving an unsaturated bond, taking advantage of the fact that thepolysilane having an alkyl group or aryl group as a side chain isdecomposed upon exposure to light and generates radical species.Unfortunately, this attempt accompanies the problem that thepolymerization efficiency is not always at a satisfactory level.

SUMMARY OF THE INVENTION

Hitherto, the application of polysilane to a resist and a polymerizationcatalyst have been aggressively studied, taking advantages of theabove-mentioned characteristics of the polysilane in that the Si--Sibond of the polysilane can be decomposed upon exposure to light.However, none of the conventional polysilanes are not practically useddue to the difficulty in decomposing the Si--Si bond.

An object of the present invention is to provide an organic siliconcompound represented by a polysilane, which is easily decomposed bylight, heat or acid, and particularly suitable for resist, and apolymerization catalyst for a compound having an unsaturated bond.

Another object of the present invention is to provide a resist capableof forming a high-precision and high-resolution pattern, and further toprovide a thermal polymerization composition and a photopolymerizationcomposition having sufficient polymerization efficiency, using theorganic silicon compound mentioned above.

The organic silicon compound of the present invention has a repeatingunit represented by general formula (I) shown below: ##STR2## wherein R¹is a t-butyl group or a pyranyl group, R² is an hydrogen atom, asubstituted or unsubstituted alkyl group having 1 to 24 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 24 carbon atoms, ora substituted or unsubstituted aralkyl group having 7 to 24 carbonatoms, R³ is a substituted or unsubstituted alkyl group having 1 to 24carbon atoms, a substituted or unsubstituted aryl group having 6 to 24carbon atoms, a substituted or unsubstituted aralkyl group having 7 to24 carbon atoms or an alkoxyl group, and k represents an integer from 0to 4.

The resist of the present invention comprises an organic siliconcompound having a repeating unit represented by the aforementionedgeneral formula (I). The resist of the present invention may contain acompound which generates an acid upon exposure to light together withthe aforementioned organic silicon compound.

The thermal polymerization composition or photopolymerizationcomposition of the present invention contains a compound having anunsaturated bond and the aforementioned organic silicon compound.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an IR spectrum of an organic silicon compound synthesized inExample 1;

FIG. 2 is a ¹ H-NMR spectrum of an organic silicon compound synthesizedin Example 1;

FIG. 3 is a ¹³ C-NMR spectrum of an organic silicon compound synthesizedin Example 1; and

FIG. 4 is a ²⁹ Si-NMR spectrum of an organic silicon compoundsynthesized in Example 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The organic silicon compound of the present invention has a specificstructure such that a t-butyl group or a pyranyl group is introduced,via an ether bond, to the p-position of a benzene nucleus of a sidechain directly binding to Si. Hereinbelow such an organic siliconcompound of the present invention will be described in detail.

The organic silicon compound of the present invention may be either amonomer or polymer. Although the organic silicon compound of the presentinvention is not limited by a molecular weight thereof, a degree ofpolymerization thereof is preferably set appropriately so as to meet theuses.

To be more specific, when the organic silicon compound of the presentinvention is used for resist, the degree of polymerization is preferablyfrom 5 to 50,000, and more preferably from 20 to 10,000. This range isdefined for the following reasons: If the degree of polymerization ofthe organic silicon compound is extremely low, it will be difficult toform resist having sufficient durability. In contrast, if the degree ofpolymerization is extremely high, the solubility of the organic siliconcompound in an organic solvent will reduce.

When the organic silicon compound of the present invention is used as aradical polymerization catalyst (radical initiator) for a compoundhaving an unsaturated bond, the degree of polymerization is preferablyfrom 1 to 50,000, and more preferably, from 5 to 10,000. This range isdefined for the following reasons: If the degree of polymerization ofthe organic silicon compound is extremely high, the compatibility of theorganic silicon compound and the compound having an unsaturated bondwill reduce, resulting in non-uniform polymerization. In the organicsilicon compound of the present invention, an Si--Si bond thereof can bereadily decomposed by light or heat and generates radicals with highefficiency. At this time, radicals are additionally generated bycleavage of a bond between Si and a benzene nucleus of a side chain.Therefore, even a monomer having alkyl groups having 1 to 16 carbonatoms at both ends of the Si atom shown in general formula (I) can beused as a polymerization catalyst for the compound having an unsaturatedbond since it generates radicals. However, since the efficiency ofradical generation is low in a monomer or an oligomer with a low degreeof polymerization, it is desired to use an organic silicon compoundhaving a degree of polymerization of 5 or more as mentioned above.

The organic silicon compound of the present invention can be synthesizedby, for example, the following method:

First, an organic silicon compound having a repeating unit representedby general formula (1) is prepared as a raw material. In the case wherea polymer of the organic silicon compound, i.e., polysilane, is used,the polysilane may be polymerized in accordance with a method ofreacting a monomer of dihalosilane corresponding to general formula (1)with a metal sodium in an appropriate solvent. After the startingorganic silicon compound is dissolved in an organic solvent such aschloroform, trifluoromethanesulfonic acid is added thereto and allowedto react under an inert gas atmosphere, thereby generating an organicsilicon compound having a repeating unit represented by general formula(2). On the other hand, p-t-butoxyhalobenzene or pyranylhalobenzene isreacted with an alkyllithium to prepare a lithium salt represented bygeneral formula (3) in advance. Then, the organic silicon compoundhaving a repeating unit represented by general formula (2) is allowed toreact with the lithium salt represented by general formula (3), therebysynthesizing the organic silicon compound of the present inventionhaving the repeating unit represented by general formula (I). In thisreaction, the lithium salt represented by general formula (3) is usedpreferably in a ratio of one equivalent or more, and more preferably, ina ratio of 1.1 equivalent or more, relative to 1 equivalent of theorganic silicon compound having the repeating unit represented bygeneral formula (2). ##STR3## wherein R² is the same as defined above.##STR4## wherein R¹, R³ and k are the same as defined above.

Hereinbelow, examples of the organic silicon compounds of the presentinvention synthesized by the aforementioned method will be given.##STR5## wherein n represents degree of polymerization.

Since the organic silicon compound of the present invention can be quiteeasily decomposed by light, heat or acid, it is extremely suitable for aresist or a polymerization catalyst for the compound having anunsaturated bond.

Hereinbelow, the resist of the present invention will be described indetail.

The resist of the present invention has at least an organic siliconcompound represented by general formula (I) and may further contain acompound which generates an acid upon exposure to light, if necessary.Because of good photoreactivity, the organic silicon compound can beused singly in resist. The resist containing an organic silicon compoundrepresented by general formula (I) and a compound which generates anacid upon exposure to light is the so-called chemical-amplification typeresist.

The organic silicon compound used in the resist of the present inventionis preferred to have a degree of polymerization from about 5 to 50,000.

Examples of compounds which generate an acid upon exposure to lightcontained together with the organic silicon compound in thechemical-amplification type resist of the present invention include asulfonium salt, an iodonium salt, a nitrobenzyl compound,naphthoquinonediazide-4-sulfonate and an azide compound. Among them, asulfornium salt is particularly preferable. Examples of the compoundswhich generate an acid upon exposure to light (to be referred to as aphotochemical acid generator) are more specifically shown below.##STR6##

In the resist of chemical-amplification type mentioned above, thephotochemical acid generator is contained preferably in the range of0.01 to 30 wt %, and more preferably in the range of 0.5 to 5 wt % basedon the amount of the organic silicon compound. This range is defined bythe following reasons: If the content is below 0.01 wt %, the reactionbetween the acid generated upon exposure to light and the organicsilicon compound will not be sufficiently carried out. In contrast, ifthe content exceeds 30 wt %, the storage stability of the resist will beprone to decrease.

The resist of the present invention as mentioned above can be preparedby dissolving the organic silicon compound, if necessary, together withthe photochemical acid generator in an appropriate solvent. Specificexamples of the organic solvents used herein include toluene, xylene,dimethylformamide, dimethylacetoamide and cellosolve.

To form a desired pattern using the resist of the present invention, thefollowing method can be used. First, the resist of the present inventionis coated on a substrate such as a silicon wafer by a spinner. Theobtained coating is then prebaked at a temperature from about 70° to120° C. and the solvent is allowed to evaporate to some extent, therebyobtaining a resist film. Subsequently, onto the surface of the resistfilm, light such as Deep UV light, KrF excimer laser light, electronicbeam or x-ray is irradiated through a predetermined mask-pattern. Afterthe completion of irradiation mentioned above, if desired, the resistmay be hard-baked at a temperature of approximately 90° to 130° C. toaccelerate the reaction of the organic silicon compound.

In the exposed part of the resist consisting of the organic siliconcompound alone, the molecular weight of the organic silicon compoundreduces since Si--Si bonds of the main chain thereof are decomposed dueto the photoreactivity of the organic silicon compound itself. When theresist is subjected to the development using a solvent such as analcohol as a developing solution and then washing, the exposed organicsilicon compound whose molecular weight has been reduced is removed bydissolving in the developing solution, while the nonexposed portion isleft unremoved, thereby forming a positive pattern. Since the organicsilicon compound of the present invention exhibits a goodphotoreactivity, a high-precision pattern excellent in resolution can beformed even when it is used singly as the resist.

In the chemical-amplification type resist containing the organic siliconcompound and the photochemical acid generator, Si--Si bonds of the mainchain of the organic silicon compound are decomposed by the reactionwith the acid generated in the exposed portion, and simultaneously, thet-butyl group or the pyranyl group of the side chain is removed to formthe hydroxyl group. The organic silicon compound having the phenolichydroxyl group can be soluble in an aqueous alkaline solution, so thatdevelopment can be performed by using an aqueous alkaline solution. Inthis case, therefore, the resist of chemical-amplification type,successfully provides a high precision pattern improved in resolutioncompared to that formed of the organic silicon compound alone.

Hereinbelow, the thermal polymerization composition andphotopolymerization composition of the present invention will beexplained. These compositions contain a compound having an unsaturatedbond and the organic silicon compound having a repeating unitrepresented by general formula (I).

The organic silicon compound used in the thermal polymerizationcomposition and photopolymerization composition of the present inventionis preferred to have a degree of polymerization of about 1 to 50,000 asmentioned above.

The compound having an unsaturated bond to be used in the thermalpolymerization composition and photopolymerization composition of thepresent invention is not particularly limited as long as the compoundcan undergo radical polymerization by cleavage of unsaturated bonds.Usable compounds having an unsaturated bond are maleimide compoundsrepresented by general formula (4) shown below, and acrylic compounds.##STR7## wherein, X is an alkylene group, cycloalkylene group, bivalenthydrocarbon group such as a monocyclic or a polycyclic arylene group, ora bivalent hydrocarbon group bonded through a bivalent atomic group suchas --CH₂ --, --CO--, --SO2-- or --CONH--.

Specific examples of the maleimide compounds includeN,N'-phenylenebismaleimide, N N'-hexamethylenebismaleimide,N,N'-methylene-di-p-phenylenebismaleimide,N,N'-oxy-di-p-phenylenebismaleimide, N,N'-4,4'-benzophenonebismaleimide,N'N-p-diphenylsulfonmaleimide,N,N'-(3,3'-dimethyl)methylene-di-p-phenylenebismaleimide,N,N'-(3,3'-diethyl)methylene-di-p-phenylenebismaleimide, andN,N'-methatoluylene-dimaleimide.

Examples of the acrylic compounds include acrylates such as 2-ethylhexylacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate andmethacrylates corresponding to the above-mentioned acrylates.

In the thermal polymerization compound or photopolymerization compoundof the present invention, the organic silicon compound is containedpreferably in the range of 0.01 to 30 wt %, and more preferably in therange of 0.1 to 10 wt % based on the amount of the compound containingan unsaturated bond. This range is defined by the following reasons: Ifthe content of the organic silicon compound is less than 0.01 wt %,polymerization of the compound having an unsaturated bond will notsufficiently proceed. In contrast, if the content exceeds 30 wt %, theinfluence of the remaining organic silicon compound used as apolymerization catalyst will be prone to be greater after thepolymerization.

In the thermal polymerization composition or photopolymerizationcomposition of the present invention, since radical species can beefficiently and easily generated by decomposing Si--Si bonds of the mainchain of the organic silicon compound, the compound having anunsaturated bond can be polymerized with sufficient polymerizationefficiency. The thermal polymerization composition of the presentinvention can be polymerized at a temperature of 200° C. or less, whichis lower than the polymerization temperature of the thermalpolymerization composition using a conventional polysilane as apolymerization catalyst. In addition, the thermal polymerizationcomposition or photopolymerization composition of the present inventionexhibits more excellent storage stability than that of a compositionusing an organic peroxide, imidazole compound, organic phosphoruscompound as a polymerization catalyst. Furthermore, in the thermalpolymerization composition or photopolymerization composition of thepresent invention, the polymerization temperature range of the compoundhaving an unsaturated bond can be appropriately adjusted by controllingthe skeleton and the bulkiness of an alkyl group, aryl group or aralkylgroup to be introduced into a side chain of the organic siliconcompound.

EXAMPLES

Hereinbelow, the present invention will be described in detail withreference to Examples.

Example 1 (Synthesis of Organic Silicon Compound)

First, phenylmethylpolysilane (10.4 g) having a degree of polymerizationof 100 was dissolved in dry dichloromethane (150 ml). To this solution,trifluoromethanesulfonic acid (7.2 ml) was added at room temperature andthe reaction was allowed to proceed for 3 hours under an argonatmosphere. After dichloromethane was removed under reduced pressure,tetrahydrofuran (80 ml) was added to the resultant solution.Subsequently, p-t-butoxyphenyllithium solution which is obtained byreacting p-t-butoxybromobenzene (20.1 g) with a 1.6M hexane solution ofn-butyllithium (104 ml), was added to this solution and the reaction wasallowed to proceed for 1.5 hours at room temperature. The generatedproduct was extracted by ethyl acetate (13 ml), followed byconcentrating under reduced pressure and purified in methanol, therebyobtaining a white crystal (4.4 g).

IR spectrum, ¹ H-NMR spectrum, ¹³ C-NMR spectrum and ²⁹ Si-NMR spectrumof the white crystal are shown in FIGS. 1 to 4. From these figures, itwas confirmed that the obtained white crystal is polysilane having arepeating unit represented by the following chemical formula. ##STR8##

Example 2 (Application to Resist)

Polysilanes represented by the following chemical formulas A to D weresynthesized in the same manner as in Example 1. For comparison,conventional polysilanes represented by the following formulas E to Gwere also synthesized. On the other hand, compounds which generate anacid upon exposure to light (photochemical acid generator), representedby the following chemical formulas a to c, were prepared. Then, resistsof sample Nos. 2-1 to 2-9 were prepared by dissolving polysilane and aphotochemical acid generator in toluene in accordance with respectiveformulations indicated in Table 1 shown later.

Patterns were formed by subjecting the resists of Nos. 2-1 to 2-9 tocoating onto a substrate, prebaking, exposure to patterned light, hardbaking and development in successive order under the respectiveconditions shown in Table 1. The sensitivity, resolution andcross-sectional shape of the obtained patterns are also shown inTable 1. As is shown in Table 1, high-precision patterns excellent inresolution were successfully formed out of the resists of Nos. 2-1 to2-6 which employed the polysilane of the present invention. Quiteexcellent patterns having a rectangular cross-sectional shape wereobtained particularly in samples of Nos. 2-1 to 2-4 using thephotochemical acid generator. ##STR9##

                                      TABLE 1                                     __________________________________________________________________________             Example                       Comparative Example                    Sample No.                                                                             1    2    3    4    5    6    7    8    9                            __________________________________________________________________________    Organic                                                                              A 100  --   --   --   100  --   --   --   --                           silicon                                                                              B --   100  --   --   --   100  --   --   --                           compound                                                                             C --   --   100  --   --   --   --   --   --                           (part by                                                                             D --   --   --   100  --   --   --   --   --                           weight)                                                                              E --   --   --   --   --   --   100  --   --                                  F --   --   --   --   --   --   --   100  --                                  G --   --   --   --   --   --   --   --   100                          Photo--                                                                              a 1    1    --   --   --   --   1    --   --                           chemical                                                                             b --   --   1    --   --   --   --   --   --                           acid   c --   --   --   1    --   --   --   --   --                           generator                                                                     (part by                                                                      weight)                                                                       Film thickness                                                                         0.5  0.5  0.5  0.5  0.5  0.5  0.5  0.5  0.5                          (μm)                                                                       Prebaking                                                                              100° C./                                                                    90°/                                                                        90° C./                                                                     110° C./                                                                    100° C./                                                                    90° C./                                                                     90° C./                                                                     90° C./                                                                     90° C./               (temp./time)                                                                           5 min.                                                                             5 min.                                                                             5 min.                                                                             5 min.                                                                             5 min.                                                                             5 min.                                                                             5 min.                                                                             5 min.                                                                             5 min.                       Light source                                                                           EB   KrF  KrF  EB   EB   KrF  KrF  EB   KrF                          (Sensitivity:                                                                          (5)  (70) (30) (5)  (5)  (70) (60) (5)  (30)                         amount of                                                                     exposure #1)                                                                  Hard baking                                                                            110° C./                                                                    110° C./                                                                    110° C./                                                                    130° C./                                                                    110° C./                                                                    110° C./                                                                    110° C./                                                                    110° C./                                                                    110° C./              (temp./time)                                                                           1 min.                                                                             1 min.                                                                             1 min.                                                                             1 min.                                                                             1 min.                                                                             1 min.                                                                             1 min.                                                                             1 min.                                                                             1 min.                       Developing                                                                             β                                                                             β                                                                             β                                                                             β                                                                             α                                                                            α                                                                            α                                                                            α                                                                            α                      solution #2                                                                   Developing                                                                             90   100  60   80   90   90   90   100  100                          time (sec.)                                                                   Resolution                                                                             0.3  0.3  0.3  0.3  0.5  0.5  0.6  0.7  0.7                          (μm)                                                                       Pattern  rec- rec- rec- rec- trape-                                                                             trape-                                                                             triangle                                                                           triangle                                                                           triangle                     cross-sectional                                                                        tangle                                                                             tangle                                                                             tangle                                                                             tangle                                                                             zoid zoid                                        shape                                                                         __________________________________________________________________________     #1: unit:                                                                     in the case of KrF  mJ/cm.sup.2  (sample Nos. 2, 3, 6, 7, 9)                  in the case of EB  μC/cm.sup.2  (sample Nos. 1, 4, 5, 8)                   #2: Developing solution                                                       α . . . ipropanol/cyclohexane mixed solution (weight ratio: 1:1)        β . . . TMAH (tetramethylammonium hydroxide) aqueous solution (2.38      wt. %)                                                                   

Example 3 (Application to Thermal Polymerization Composition)

Bismaleimide compounds X, Y and Z represented by the following chemicalformulas were prepared as a compound having an unsaturated bond. Inaddition, polysilanes A and B used in Example 2 and conventionalpolysilane H represented by the following formula, were prepared as apolymerization catalyst.

As shown in Table 2, a bismaleimide compound (100 g) and a polysilane (1g) were mixed to prepare thermal polymerization compositions of Nos. 3-1to 3-5. The gelation time of each of thermal polymerization compositionswas measured on hot plate at various temperatures. The results are shownin Table 2.

As is apparent from table 2, thermal polymerization compositions of Nos.3-to 3-3 using the polysilane of the present invention can besufficiently polymerized even in a temperature range of 200° C. or less.It is suggested that these polysilanes may have a latent propertyjudging form the fact that the reaction abruptly proceeded at a certaintemperature or more. ##STR10##

                                      TABLE 2                                     __________________________________________________________________________                Example           Comparative Example                             Sample No.  3-1   3-2   3-3   3-4   3-5                                       __________________________________________________________________________    bismaleimide                                                                          X   100   --    --    100   --                                        (parts by weight)                                                                     Y   --    100   --    --    100                                               Z   --    --    100   --    --                                        polysilane                                                                            A   1     --    1     --    --                                        (part by weight)                                                                      B   --    1     --    --    --                                                H   --    --    --    1     1                                         gelation time at                                                                      170° C.                                                                    >20                                                                              min                                                                              >20                                                                              min                                                                              >20                                                                              min                                                                              >20                                                                              min                                                                              >20                                                                              min                                            180° C.                                                                    64 sec                                                                              60 sec                                                                              65 sec                                                                              20 min                                                                              20 min                                            200° C.                                                                    43 sec                                                                              40 sec                                                                              45 sec                                                                              150                                                                              sec                                                                              160                                                                              sec                                            220° C.                                                                    20 sec                                                                              15 sec                                                                              20 sec                                                                              100                                                                              sec                                                                              120                                                                              sec                                    __________________________________________________________________________

Further, thermal polymerization composition of No. 3-1 was dissolved in1,4-dioxane (400 g) and allowed to stand still for several days at roomtemperature. The composition exhibited a good storage stability withoutparticular changes.

On the other hand, the similar storage stability test was applied to thethermal polymerization composition prepared in the same manner as in thepreparation of sample No. 3-1 except that an organic peroxiderepresented by the following formula was used instead of polysilane A ofthe present invention. In the thermal polymerization composition allowedto stand still for 24 hours, the polymerization proceeded and aprecipitate insoluble in 1,4-dioxane was generated.

From the results in the foregoing, it was confirmed that the thermalpolymerization composition using the polysilane of the present inventionas a polymerization catalyst exhibited an excellent storage stabilitycompared to that using a peroxide. ##STR11##

Example 4 (Application to Photopolymerization Composition)

Methacrylates P, Q and R represented by the following chemical formulaswere prepared as a compound having an unsaturated bond. In addition, thepolysilanes of the present invention, B and C used in Example 2 andconventional polysilane H were prepared as a polymerization catalyst.

A methacrylate and a polysilane were mixed in accordance with theformulations shown in Table 3 to prepare photopolymerizationcompositions of Nos. 4-1 to 4-4.

Subsequently, each of the photopolymerization compositions was coatedonto an aluminum substrate. Onto the coating, ultraviolet light wasirradiated from a high-pressure mercury lamp positioned at 15 cm apart,in an irradiation amount of 80 W/cm for 10 seconds to polymerize themethacrylate.

As a result, tack-free coatings were obtained from samples of Nos. 4-1to 4-3 which employed the polysilane of the present invention as apolymerization catalyst. Whereas, the coating formed of sample No. 4--4using a conventional polysilane was slightly tacky.

From the results in the foregoing, it was found that thephotopolymerization composition exhibiting sufficient polymerizationefficiency can be obtained by using the polysilane of the presentinvention as a polymerization catalyst for a compound having anunsaturated bond. ##STR12##

                  TABLE 3                                                         ______________________________________                                                                 Comparative                                                      Example      Example                                              Sample No.    4-1    4-2      4-3  4-4                                        ______________________________________                                        methacrylate                                                                            P       20     --     --   20                                       (parts by weight)                                                                       Q       --     20     --   --                                                 R       --     --     40   --                                       polysilane                                                                              B       1      --     1    --                                       (parts by weight)                                                                       C       --     1      --   --                                                 H       --     --     --   1                                        ______________________________________                                    

What is claimed is:
 1. An organic silicon compound having a repeatingunit represented by general formula (I) shown below: ##STR13## whereinR¹ is a t-butyl group, R² is an hydrogen atom, a alkyl group having 1 to24 carbon atoms, a aryl group having 6 to 24 carbon atoms, or a aralkylgroup having 7 to 24 carbon atoms, R³ is a alkyl group having 1 to 24carbon atoms, a aryl group having 6 to 24 carbon atoms, a aralkyl grouphaving 7 to 24 carbon atoms or an alkoxyl group, and k represents aninteger from 0 to
 4. 2. A resist comprisingan organic silicon compoundhaving a repeating unit represented by general formula (I) shown below:##STR14## wherein R¹ is a t-butyl group, R² is an hydrogen atom, a alkylgroup having 1 to 24 carbon atoms, a aryl group having 6 to 24 carbonatoms, or a aralkyl group having 7 to 24 carbon atoms, R³ is a alkylgroup having 1 to 24 carbon atoms, a aryl group having 6 to 24 carbonatoms, a aralkyl group having 7 to 24 carbon atoms or an alkoxyl group,and k represents an integer from 0 to
 4. 3. The resist according toclaim 2, wherein said organic silicon compound has a degree ofpolymerization of 5 to 50,000.
 4. The resist according to claim 3,wherein said organic silicon compound has a degree of polymerization of20 to 10,000.
 5. The resist according to claim 2, further comprising acompound which generates an acid upon exposure to light.
 6. The resistaccording to claim 5, wherein said compound which generates an acid uponexposure to light is contained in the range of 0.01 to 30 wt % based onthe amount of the organic silicon compound.
 7. The resist according toclaim 6, wherein said compound which generates an acid upon exposure tolight is contained in the range of 0.5 to 5 wt % based on the amount ofthe organic silicon compound.
 8. A thermal polymerization compositioncomprising in admixture,a compound having an unsaturated bond, anorganic silicon compound having a repeating unit represented by generalformula (I) shown below: ##STR15## wherein R¹ is a t-butyl group, R² isan hydrogen atom, a alkyl group having 1 to 24 carbon atoms, a arylgroup having 6 to 24 carbon atoms, or a aralkyl group having 7 to 24carbon atoms, R³ is a alkyl group having 1 to 24 carbon atoms, a arylgroup having 6 to 24 carbon atoms, a substituted or unsubstitutedaralkyl group having 7 to 24 carbon atoms or an alkoxyl group, and krepresents an integer from 0 to
 4. 9. The composition according to claim8, wherein said compound having an unsaturated bond is a maleimidecompound or an acrylic compound.
 10. The composition according to claim8, wherein said organic silicon compound is contained in the range of0.01 to 30 wt % based on the amount of the compound having anunsaturated bond.
 11. The composition according to claim 10, whereinsaid organic silicon compound is contained in the range of 0.1 to 10 wt% based on the amount of the compound having an unsaturated bond. 12.The composition according to claim 8, wherein said organic siliconcompound has a degree of polymerization of 1 to 50,000.
 13. Thecomposition according to claim 12, wherein said organic silicon compoundhas a degree of polymerization of 5 to 10,000.
 14. A photopolymerizationcomposition comprising in admixture,a compound having an unsaturatedbond, and an organic silicon compound having a repeating unitrepresented by general formula (I) shown below: ##STR16## wherein R¹ isa t-butyl group, R2 is an hydrogen atom, a alkyl group having 1 to 24carbon atoms, a aryl group having 6 to 24 carbon atoms, or a aralkylgroup having 7 to 24 carbon atoms, R³ is a alkyl group having 1 to 24carbon atoms, a aryl group having 6 to 24 carbon atoms, a aralkyl grouphaving 7 to 24 carbon atoms or an alkoxyl group, and k represents aninteger from 0 to
 4. 15. The composition according to claim 14, whereinsaid compound having an unsaturated bond is a maleimide compound or anacrylic compound.
 16. The composition according to claim 14, whereinsaid organic silicon compound is contained in the range of 0.01 to 30 wt% based on the amount of the compound having an unsaturated bond. 17.The composition according to claim 16, wherein said organic siliconcompound is contained in the range of 0.1 to 10 wt % based on the amountof the compound having an unsaturated bond.
 18. The compositionaccording to claim 14, wherein said organic silicon compound has adegree of polymerization of 1 to 50,000.
 19. The composition accordingto claim 18, wherein said organic silicon compound has a degree ofpolymerization of 5 to 10,000.